評論Cassandra的密鑰空間，表格，列

Question

在Oracle中，有關於表格，視圖，實例化視圖或列到數據字典中的列的可能性add a comment，例如，

COMMENT ON COLUMN employees.job_id 
    IS 'abbreviated job title'; 

我試圖瞭解這不一定是自explanable和大型數據庫（200表）的名字背後的想法時，發現了這個特別有用的測試儀。

卡桑德拉有這樣的功能嗎？

Answer 1

您可以使用 '與註釋' 選項

cqlsh:d2> 
cqlsh:d2> create table employee (id int primary key, name text) with comment = 'Employee id and name'; 
cqlsh:d2> desc table employee; 

CREATE TABLE d2.employee (
    id int PRIMARY KEY, 
    name text 
) WITH bloom_filter_fp_chance = 0.01 
    AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}' 
    AND comment = 'Employee id and name' 
    AND compaction = {'min_threshold': '4', 'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy', 'max_threshold': '32'} 
    AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'} 
    AND dclocal_read_repair_chance = 0.1 
    AND default_time_to_live = 0 
    AND gc_grace_seconds = 864000 
    AND max_index_interval = 2048 
    AND memtable_flush_period_in_ms = 0 
    AND min_index_interval = 128 
    AND read_repair_chance = 0.0 
    AND speculative_retry = '99.0PERCENTILE'; 

Cassandra documentation